/*******************************************************************************
 * The MIT License (MIT)
 *
 * Copyright (c) 2022, DigiDNA
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the Software), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 ******************************************************************************/

import Cocoa

@objc
class LightnessPairItem: NSObject
{
    @objc class LightnessVariant: NSObject
    {
        @objc public dynamic      var lightness: CGFloat = 0
        @objc public dynamic weak var base:      ColorItem?
        @objc public dynamic      var name:      String?

        @objc public private( set ) dynamic var labelColor: NSColor?
        @objc public private( set ) dynamic var color:      NSColor?

        private var observations = [ NSKeyValueObservation ]()

        init( base: ColorItem? )
        {
            self.base = base

            super.init()

            let o1 = self.observe( \.lightness ) { [ weak self ] o, c in self?.update() }
            let o2 = self.observe( \.base      ) { [ weak self ] o, c in self?.update() }

            self.observations.append( contentsOf: [ o1, o2 ] )
        }

        private func update()
        {
            self.labelColor = ( self.lightness < 0.5 ) ? NSColor.white : NSColor.black

            if let color = self.base?.color
            {
                self.color = color.usingColorSpace( .sRGB )?.byChangingLightness( self.lightness )
            }
        }
    }

    @objc public private( set ) dynamic var lightness1: LightnessVariant
    @objc public private( set ) dynamic var lightness2: LightnessVariant

    public var onEdit:   ( ( LightnessPairItem ) -> Void )?
    public var onDelete: ( ( LightnessPairItem ) -> Void )?

    init( base: ColorItem? )
    {
        self.lightness1 = LightnessVariant( base: base )
        self.lightness2 = LightnessVariant( base: base )
    }
}
